Method of manufacturing a catheter sheath

ABSTRACT

A catheter sheath comprises a tubular member connected to a catheter handle, the tubular sheath including one or more electrical conductors and one or more electrode rings attached to the tip of the tubular member. The tubular member further includes at least one opening that allows the one or more electrical conductor to be electrically connected to the one or more electrode rings. The electrode ring is slid over the tubular member so as to cover the opening. The tubular member and the electrode ring are subjected to heat treatment by induction heating so that the material of the tubular member melts locally around the electrode ring to form a seal between the tubular member and the electrode ring.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/816,729, filed Feb. 12, 2013, pending, which is a national phaseentry under 35 U.S.C. §371 of International Patent ApplicationPCT/AU2011/001010, filed Aug. 12, 2011, designating the United States ofAmerica and published in English as International Patent Publication WO2012/019225 A1 on Feb. 16, 2012, which claims the benefit under Article8 of the Patent Cooperation Treaty and under 35 U.S.C. §119(e) to U.S.Provisional Patent Application Ser. Nos. 61/373,725, filed Aug. 13,2010, and 61/409,006, filed Nov. 1, 2010, the disclosure of each ofwhich is hereby incorporated herein by this reference in its entirety.

TECHNICAL FIELD

This application relates to a catheter sheath and a method formanufacturing a catheter sheath. In particular, this application relatesto a method for attaching an electrode to a catheter sheath of acatheter assembly.

BACKGROUND

Any discussion of the prior art throughout the specification should inno way be considered as an admission that such prior art is widely knownor forms part of common general knowledge in the field.

Catheters are commonly used in medical practice to examine and treat theheart. They may be inserted into the cardiovascular system of thepatient through small punctures in the skin. They may then extendthrough a vein into the heart where they sense the electrical activityof the heart. In certain types of aberrant electrical activity, somecatheters may be able to treat the heart by ablating certain areas ofthe heart. Catheters typically include a tubular structure such as aplastic tube with one or more electrodes attached to the tip of thetube.

Many catheters use conductive metal rings as electrodes. These metalrings are positioned at various intervals along the length of the tipsection of the tube. These types of ring electrodes may be used forvarious tasks including radiopaque markers, antennas, and sensors forsensing electrical signals. Typically, the rings are secured in placeusing an appropriate adhesive, or by some mechanical means such ascrimping or swaging. Swaging is a process of reducing the diameter of aductile metal tube to a smaller, predetermined diameter.

The problem with mechanical attachment is that it may allow fluid topass between the ring and the tube. Biological fluid may then enter thetube, and may be trapped under the electrode ring or within thecatheter.

An adhesive may be used to seal the region between the ring and thetube. The adhesive may also be applied to the margins or edges of thering electrode to further improve the seal between the ring electrodeand the catheter tube. The use of adhesives may, however, be problematicbecause particles of the resin may become detached from the cathetertube during use. This is undesirable as it presents a risk to thepatient. In addition, the application process of the adhesive requiresprecision and makes the manufacturing process of the catheter slower andmore expensive.

These problems are exacerbated for catheters that are reprocessed orreused. When a catheter tube is cleaned and sterilized after it has beenused, the mechanical joint between the ring electrodes and the cathetertube may be weakened and biological matter may enter the catheter tube.Weakening of the joints and resulting failure can be particularly commonafter multiple reprocessing cycles. It is also possible for smallparticles of the adhesive to become detached during reprocessing leavingsmall cavities in the resin. These cavities may catch biological matterwhen the catheter is used, and the biological matter may, in turn, betransferred to another patient because these types of small cavities maybe difficult to clean.

BRIEF SUMMARY

It is an object of the present invention to overcome or ameliorate atleast one of the disadvantages of the prior art, or to provide a usefulalternative.

According to the present invention, there is provided a method ofmanufacturing a catheter sheath including: providing a tubular member ofnon-conductive material having a proximal end and a distal end, thetubular member further having one or more electrical conductorsextending from the proximal end to the distal end within the tubularmember, forming at least one opening in an outer wall of the tubularmember for accessing the at least one electrical conductor within thetubular member, and attaching at least one conductive element on theouter wall of the tubular member in conductive connection with the atleast one electrical conductor so that the at least one conductiveelement is adjacent to and surrounding the opening, and treating thetubular member and the at least one conductive element with heat byinduction heating so that the tubular member melts locally around the atleast one conductive element to form a seal along each edge of theconductive element. The at least one conductive element may include aring electrode that is a snug fit about the tubular member.

An embodiment of the invention provides that attaching the at least oneconductive element on the tubular member is arranged by a radiallyapplied force. The radially applied force may compress the at least oneconductive element so that an outer surface of the at least oneconductive element lies substantially flush with the outer wall of thetubular member. The radial force may include swaging.

According to an embodiment of the invention, a sacrificial heat-shrinkover the at least one conductive element is applied during the heattreatment. A mold may alternatively be applied over the at least oneconductive element during the heat treatment.

According to an embodiment of the invention, the one or more electricalconductors are arranged within a lumen defined by the tubular member.However, the one or more electrical conductors may also be arrangedbetween inner and outer walls of the tubular member.

In a second aspect, there is provided a catheter sheath comprising: atubular member of non-conductive material having a proximal end and adistal end, at least one electrical conductor extending from theproximal end to the distal end within the tubular member, at least oneopening in an outer wall of the tubular member for accessing the atleast one electrical conductor within the tubular member, and at leastone conductive element on the outer wall of the tubular member, the atleast one conductive element being adjacent to and surrounding theopening and arranged in conductive connection with the at least oneelectrical conductor, wherein the tubular member is arranged to form aseal along each edge of the at least one conductive element by heattreating the tubular member by induction heating so that the tubularmember melts locally around the at least one conductive element. The atleast one conductive element may be a ring electrode that is a snug fitabout the tubular member.

According to an embodiment of the invention, the at least one conductiveelement is attached to the tubular member by a radially applied force.The radially applied force may be arranged to compress the at least oneconductive element so that an outer surface of the at least oneconductive element is substantially flush with the outer wall of thetubular member. The radially applied force may include swaging.

According to an embodiment of the invention, the seal is arranged byapplying a sacrificial heat-shrink over the at least one conductiveelement during the heat treatment. The seal may also be arranged byapplying a mold over the at least one conductive element during the heattreatment.

According to an embodiment of the invention, the at least one electricalconductor is arranged between an inner and outer wall of the tubularmember. The at least one electrical connector may also be arrangedlongitudinally within a lumen defined by the tubular member.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way ofexample only, with reference to the accompanying drawings in which:

FIG. 1 shows a catheter assembly including an embodiment of a cathetersheath of the catheter assembly;

FIGS. 2a-2f are schematic views that show the steps of manufacturing atubular member used in the method of manufacturing a catheter sheath;

FIGS. 3a-3c are schematic views that illustrate the steps ofmanufacturing another type of tubular member used in the method ofmanufacturing a catheter sheath;

FIGS. 4a and 4b are schematic views that show a longitudinalcross-sectional side view of the tubular member with the ring electrode,before and after the heat treatment;

FIGS. 5a and 5b are schematic views that illustrate a longitudinalcross-sectional side view of the tubular member when the ring electrodeis swaged onto the tubular member, before and after heat treatment;

FIG. 6a shows a schematic side view of a step of attaching a ringelectrode onto the catheter sheath by heat treating the sheath and usinga die or a mold in the process of manufacturing a catheter sheath;

FIG. 6b shows a schematic side view of the distal end of the tubularmember once the tubular member has been subjected to heat treatment byinduction heating;

FIG. 7a shows a schematic side view of a step of attaching a ringelectrode onto the tubular member by heat treating the sheath byinduction heating and by using a heat-shrink to mold the sheath in theprocess of manufacturing a catheter sheath; and

FIG. 7b shows a schematic side view of the distal end of the tubularmember once the tubular member has been subjected to heat treatment byinduction heating.

DETAILED DESCRIPTION

FIG. 1 depicts a heart catheter 10. The catheter includes a handle 11,and an elongate catheter sheath 12 extending from the handle 11. Thecatheter sheath 12 consists of a generally tubular member 14 having aproximal end 16 connected to the handle 11 and a distal end 18 havingone or more electrodes 20 attached to the tubular member 14.

The electrodes 20 are in predetermined, axially spaced locations betweenthe proximal end 16 and the distal end 18 of the tubular member 14.Although electrodes of different shapes may be used, an annularelectrode ring 20 having an inside diameter equal to or greater than theoutside diameter of the tubular member 14 is shown in the accompanyingfigures. The electrode ring 20 is preferably a platinum-iridium ring butmay be made of other suitable conductive material. The inner diameter ofeach ring approximates the outer diameter of the tubular member 14 sothat each ring electrode 20 is a snug fit about an external surface ofthe tubular member 14.

The tubular member 14 includes conductors (not shown in FIG. 1) that areconnected to the electrodes 20 at the distal end 18 of the tubularmember 14. The conductors are able to carry the signal sensed by theelectrodes 20 through the tubular member 14 to the handle 11 where theconductors 30 further connect to electrical instruments, for example, toa monitor, a stimulator, or a source of energy such as an RF energysource used for ablation. At least one conductor may be associated withan electrode 20, but several conductors may be required for oneelectrode. The tubular member 14 is preferably formed of a biocompatibleand resilient material that is non-conductive. Polymeric materials suchas a polyether block amide (PEBAX), silicone or polyurethane may beused.

FIGS. 2a-2f are schematic views that show a close-up of the distal end18 of the tubular member 14 as a series of figures illustrating themanufacturing process of the catheter member 14. In this embodiment, thetubular member 14 is initially formed by an inner tubular section 32defining an elongate lumen 31 within the tubular member 14. A pluralityof conductors 30, one of which is shown in FIG. 2b , is helically woundabout an outer surface 34 of the inner tubular section 32. A coating 36of a plastic material is laid over the conductors 30 to sandwich theconductors between the inner section 32 and the coating 36 as shown inFIG. 2 c.

To attach one or more electrodes to the distal end 18 of the tubularmember 14, an opening 28 is formed on the outer wall of the tubularmember 14 as seen in FIG. 2d . The opening 28 is formed, for example, bylaser cutting a portion 38 out of the tubular member 14. Laser cuttingfacilitates accurate cutting of the tubular member 14 and only thedesired conductor or conductors 30 are revealed by cutting the portion38 out of the tubular member. As seen in FIG. 2d , the opening 28reveals one or more conductors 30 that are to be connected with anelectrode 20. The opening 28 is filled with a suitable biocompatibleadhesive 39 such as an epoxy adhesive as shown in FIG. 2e . The ringelectrode is then slipped onto the tubular member to cover the opening28 so that the ring electrode 20 is adjacent to and surrounding theopening 28 as seen in FIG. 2f . The epoxy adhesive 39 inserted into theopening is electrically conductive and, therefore, it ensures theconductive connection between the conductor 30 and the ring electrode20.

With reference to FIGS. 3a -3 c, another type of tubular member isprovided. The tubular member 14 in FIGS. 3a-3c defines one or moreelongate passages, lumens, 22, 24 and 26 that extend longitudinallythrough the tubular member 14. The lumens can be used, for example, tohouse a deflection stylet for a deflection type catheter, or one or moreelectrical conductors 30 extending through the tubular member 14 fromthe distal end 18 of the tubular member to the proximal end 16 of thetubular member. In this type of catheter sheath 14, the conductors runlongitudinally within one of the lumens 22, 24, 26. To attach one ormore electrodes 20 to the distal end 18 of the tubular member 14, anopening 28 is formed on the outer wall of the tubular member 14 so thatthe conductor or conductors 30 may be drawn out of the tubular member tobe connected to a respective electrode 20. The opening 28 extends fromthe lumen inside the tubular member 14 to the outside surface of thetubular member. As seen in FIG. 3b , the conductor or conductors 30 arepreferably connected to the inner surface of the ring electrode 20. Thisconductive connection is provided by welding, soldering or any othersuitable method. Induction welding is preferred as it provides aconsistent result. No new materials need to be introduced whenconnecting the conductor 30 to the ring electrode 20 by inductionwelding, induction welding thus eliminating the need for anyintermediate materials. With reference to FIG. 3c , once the conductor30 is conductively connected to the electrode, the ring electrode 20 isslipped over the distal end 18 of the tubular member 14 to a positiondirectly over the opening while drawing any excess length of theconductor 30 back into the lumen of the tubular member 14.

Once the ring electrode 20 is slipped onto the tubular member 14adjacent to and surrounding the opening 28, it is then secured in placeby heating and melting the tubular member around the electrode ring 20.Bonding of the electrode 20 to the tubular member 14 occurs as meltedplastic of the tubular member 14 around the electrode ring 20 solidifiesas it cools down. Most heating methods include an external heat sourcesuch as a hot air gun, or an oven. A method based on induction bondinghas a number of advantages over these methods and it is, therefore, usedto heat and melt the tubular member 14 surrounding the ring electrode 20to form a seal between the electrode 20 and the opening 28. Inductionheating can be used to heat, melt or solder an electrically conductingarticle such as the ring electrode 20. An induction heater used to treatthe tubular member 14 consists typically of a power supply that providesa high frequency alternating current that is passed through a coil. Thetubular member 14 with the electrode ring 20 attached onto it isinserted through the coil. Current is induced within the electrode ringplaced in the coil, causing resistive heating of the metal ring 20. Asthe temperature of the ring electrode 20 increases, it melts the plastictubular member 14 locally around the ring electrode 20 and bonds the twomaterials together. Induction heating is fast, clean and simpler to dothan traditional methods to manufacture an electrode ring assembly.Depending on the size of the coil, induction heating allows targetedheating to relatively small areas and is particularly useful for heatingor soldering elongated rod-like articles. During the heating process,mandrels may be inserted into the lumen of the catheter sheath tosupport the tubular member and inhibit the collapse or deformation ofthe tubular member 14.

FIGS. 4a and 4b, 5a and 5b, 6a and 6b, and 7a and 7b depict the tubularmember 14 during the process of attaching the ring electrode orelectrodes 20 onto the tubular member 14.

FIGS. 4a and 4b depict the connection between the electrode ring 20 andthe tubular member 14 as a longitudinal cross-section through thetubular member 14 so that only one side of the connection between theelectrode ring 20 and the tubular member 14 is shown. As the electrodering 20 is slid onto the tubular member 14, a small gap 40 remainsbetween the electrode ring 20 and the tubular member 14 as shown in FIG.4a . This small gap 40 can be filled by locally heating and melting theplastic substrate of the tubular member 14 around the electrode ring 20to form a seal between electrode ring 20 and the tubular member 14. FIG.4b depicts the connection between the tubular member 14 and theelectrode ring 20 after the sealing by induction heating has occurred.The tubular member 14 has melted around the ring and now forms a fillet48 after cooling. This fillet 48 provides enhanced bond strength andhelps to prevent biological material from being caught adjacent to theelectrode 20.

The bond between the electrode ring 20 and the catheter sheath 14 can beimproved by swaging or another suitable mechanical compression methodsuch as crimping (not shown in the accompanying drawings). Swaging is aprocess for shaping metallic articles such as rods, bars, or tubes. Inparticular, it can be used to reduce the diameter of such articles, orproducing a taper in them. Once the ring electrode 20 has been slid intoits place covering the opening 28, its diameter is reduced by swagingthus making the ring electrode tightly secure in its position on thetubular member 14. During swaging, the tubular member 14 with theelectrode ring 20 is placed inside a die that applies compressive forceby hammering and rotating around the ring. Alternatively, a mandrel canbe inserted inside the tubular member during compression. Once theswaging process is complete, the outer diameter of the ring electrode 20is substantially the same as the outer diameter of the tubular member14.

FIG. 5a shows in schematic view the connection between the tubularmember 14 and the electrode ring 20 when the electrode ring 20 has beensecured in its place by swaging. Swaging has reduced the diameter of thering electrode 20 and the electrode 20 has been compressed into thetubular member 14 as can be seen in FIG. 5a . Although the electrodering 20 has been compressed into the sheath 14 so as to be flush withthe sheath 14, a transition zone 42 remains adjacent to the ringelectrode 20 where the plastic tubular member 14 has been compressed.The transition zone 42 runs circumferentially around the tubular member14 in close proximity to the electrode ring 20. FIG. 5b shows thetubular member 14 and the electrode ring 20 after the tubular member 14with the electrode ring 20 has been exposed to induction heating. Thesmall transition zone 42 has been filled as the plastic material of thetubular member 14 has melted and solidified upon cooling tightly aroundthe electrode ring 20. This provides a tight seal between the electrodering 20 and the opening 28.

FIG. 6a shows in a schematic view a longitudinal cross-sectional view ofthe tubular member 14 with the electrode ring 20 swaged onto it. A moldor die 44 can further be used when manufacturing the catheter sheath 12to ensure that the molten plastic of the tubular member 14 fills anygaps adjacent to the ring electrode 20. During the manufacturingprocess, the mold or die 44 covers the tubular member 14 and theelectrode 20 so that upon melting and cooling, the surface of the ringbecomes flush with the surface of the tubular member 14. As can be seenfrom FIG. 6b , the transition zone 42 formed during swaging is filledwith the plastic of the tubular member 14 after the induction heatinghas been effected and the electrode ring 20 is flush with the outsidesurface of the tubular member 14.

FIG. 7a shows the use of a sacrificial heat-shrink sleeve or othersuitable tubing placed over the electrode ring 20. Upon heating, theelectrode ring 20 conducts heat to the shrink sleeve, which in turnmelts and molds the plastic tubular member 14 so that the outer surfaceof the electrode ring 20 is flush with the surface of the tubular member14. It can be seen from FIG. 7b that the transition zone 42 formedduring swaging (seen in FIG. 7a ) has been filled with plastic after thebonding by induction heating has occurred. The distal end of the tubularmember 14 is heated using a controlled heat source providing heating byinduction. Heating of the tubular member 14 causes the material of thetubular member 14 to liquefy to an extent and to flow together causingclosure of the transition zone 42. In addition, radial expansion of thetubular member material takes place, the extent of the radial expansionbeing constrained by the sleeve 46.

The advantage of the present catheter sheath and its manufacturingmethod is that it provides a tight seal between the electrode ring 20and the tubular member 14, resulting in no fluid or other substance tobe able to pass underneath the electrode ring. It is a further advantagethat adhesion between the electrode ring and the tubular member 14 isenhanced without using any adhesives. Treating the tubular member 14 andthe electrode ring 20 by induction heating further assures a smoothtransition between the outer circumferential surface of the ringelectrode 20 and the outer circumferential surface of the tubular member14. It is a further advantage that the method of manufacturing of thecatheter sheath simplifies the procedure of producing a suitablecatheter sheath. In addition, the use of the induction heating techniqueto cause flow of the material of the tubular sheath 14 assists insealing the tubular member against the ingress of foreign material. Thisheating technique also serves to assist in retaining the electrodes inposition on the catheter sheath and makes it thus more durable.

Reference throughout this specification to “one embodiment,” “someembodiments” or “an embodiment” means that a particular feature,structure or characteristic described in connection with the embodimentis included in at least one embodiment of the present invention. Thus,appearances of the phrases “in one embodiment,” “in some embodiments” or“in an embodiment” in various places throughout this specification arenot necessarily all referring to the same embodiment, but may.Furthermore, the particular features, structures or characteristics inone or more embodiments may be combined in any suitable manner, as wouldbe apparent to one of ordinary skill in the art from this disclosure.

As used herein, unless otherwise specified, the use of ordinaladjectives “first,” “second,” “third,” etc., to describe a commonobject, merely indicate that different instances of like objects arereferred to, and are not intended to imply that the objects so describedmust be in a given sequence, either temporally, spatially, in ranking,or in any other manner.

In the claims below and the description herein, any one of the terms“comprising,” “comprised of,” or “which comprises” is an open term thatmeans including at least the elements/features that follow, but notexcluding others. Thus, the term “comprising,” when used in the claims,should not be interpreted as being limitative to the means or elementsor steps listed thereafter. For example, the scope of the expression “adevice comprising A and B” should not be limited to devices consistingonly of elements A and B. Any one of the terms “including,” “whichincludes” or “that includes,” as used herein, is also an open term thatalso means including at least the elements/features that follow theterm, but not excluding others. Thus, “including” is synonymous with andmeans “comprising.”

It should be appreciated that in the above description of exemplaryembodiments of the invention, various features of the invention aresometimes grouped together in a single embodiment, figure, ordescription thereof for the purpose of streamlining the disclosure andaiding in the understanding of one or more of the various inventiveaspects. This method of disclosure, however, is not to be interpreted asreflecting an intention that the claimed invention requires morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive aspects lie in less than allfeatures of a single foregoing disclosed embodiment. Thus, the claimsfollowing the Detailed Description are hereby expressly incorporatedinto this Detailed Description, with each claim standing on its own as aseparate embodiment of this invention.

Furthermore, while some embodiments described herein include some butnot other features included in other embodiments, combinations offeatures of different embodiments are meant to be within the scope ofthe invention, and form different embodiments, as would be understood bythose skilled in the art. For example, in the following claims, any ofthe claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are setforth. However, it is understood that embodiments of the invention maybe practiced without these specific details. In other instances,well-known methods, structures and techniques have not been shown indetail in order not to obscure an understanding of this description.

Similarly, it is to be noticed that the term coupled, when used in theclaims, should not be interpreted as being limited to direct connectionsonly. The terms “coupled” and “connected,” along with their derivatives,may be used. It should be understood that these terms are not intendedas synonyms for each other. Thus, the scope of the expression “a deviceA coupled to a device B” should not be limited to devices or systemswherein an output of device A is directly connected to an input ofdevice B. It means that there exists a path between an output of A andan input of B, which may be a path including other devices or means.“Coupled” may mean that two or more elements are either in directphysical or electrical contact, or that two or more elements are not indirect contact with each other but yet still co-operate or interact witheach other.

Thus, while there has been described what are believed to be thepreferred embodiments of the invention, those skilled in the art willrecognize that other and further modifications may be made theretowithout departing from the spirit of the invention, and it is intendedto claim all such changes and modifications as falling within the scopeof the invention. For example, any formulas given above are merelyrepresentative of procedures that may be used. Functionality may beadded or deleted from the block diagrams and operations may beinterchanged among functional blocks. Steps may be added or deleted tomethods described within the scope of the invention.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the disclosure as shownin the specific embodiments without departing from the scope of thedisclosure as broadly described. The present embodiments are, therefore,to be considered in all respects as illustrative and not restrictive.

1.-20. (canceled)
 21. A method of manufacturing a catheter sheath,comprising the steps of: providing a tubular member of non-conductivematerial having a proximal end and a distal end; forming at least oneopening in an outer wall of the tubular member; attaching at least oneconductive element on the outer wall of the tubular member; and heatingby induction the at least one conductive element in which the inductionheat is directly conducted by only the at least one conductive element,such that indirect heat from the induction heated at least oneconductive element causes local melting of the tubular member.
 22. Themethod of claim 21, wherein attaching the at least one conductiveelement on the tubular member comprises applying a radial force.
 23. Themethod of claim 22, wherein applying the radial force compresses the atleast one conductive element so that an outer surface of the at leastone conductive element lies substantially flush with the outer wall ofthe tubular member.
 24. The method of claim 22, further comprisingswaging the at least one conductive element.
 25. The method of claim 21,further comprising applying a sacrificial heat-shrink member over the atleast one conductive element.
 26. The method of claim 21, wherein one ormore electrical conductors are arranged within a lumen defined by thetubular member.
 27. The method of claim 21, wherein one or moreelectrical conductors are arranged between an inner wall and an outerwall of the tubular member.
 28. The method of claim 21, wherein the atleast one conductive element includes a ring electrode snug fit aboutthe tubular member.
 29. The method of claim 23, further comprisingswaging the at least one conductive element.
 30. The method of claim 21,wherein the at least one conductive element comprises a conductive ring,and further comprising, prior to the induction heating, reducing adiameter of the conductive ring after the placing on the outer wall ofthe tubular member to be flush with a diameter of the tubular member.31. The method of claim 21, further comprising placing a mold about theat least one conductive element and longitudinally adjacent outer wallof the tubular member prior to the induction heating and constrainingthe local melting of the tubular member to fill a transition zoneadjacent the at least one conductive element with the mold.
 32. Themethod of claim 21, further comprising placing a sacrificial heat-shrinksleeve about the conductive ring and longitudinally adjacent outer wallof the tubular member prior to the induction heating, shrinking theheat-shrink sleeve responsive to the induction heating of the at leastone conductive element and constraining the local melting of the tubularmember to fill the transition zone.
 33. A catheter sheath, comprising: atubular member of non-conductive material having a proximal end and adistal end; at least one electrical conductor extending from theproximal end to the distal end within the tubular member; at least oneopening in an outer wall of the tubular member for accessing the atleast one electrical conductor within the tubular member; at least oneconductive element on the outer wall of the tubular member, the at leastone conductive element being adjacent to and surrounding the at leastone opening and arranged in conductive connection with the at least oneelectrical conductor; and a seal, formed by induction heating, alongeach edge of the at least one conductive element comprising locallymelted and re-solidified material of the tubular member.